Reprinted from JAMA @ The Journal of the American Medical Association

October 2, 1996 Volume 276

Copyright 1996,
American
Medical Association
Original
Contributions
Differences in 4-Year Health Outcomes
for Elderly and Poor, Chronically III
Patients Treated in HMO and
Fee-for-Service
Systems
Results From the Medical Outcomes Study
John E. Ware, Jr, PhD; Martha S. Bayliss, MSc; William H. Rogers, PhD; Mark Kosinski, MA; Alvin R. Tarlov, MD
Objective To compare physical and mental health outcomes of chronically ill
adults, including elderly and poor subgroups, treated in health maintenance orga-
nization (HMO) and fee-for-service (FFS) systems.
Study Design A 4-year observational study of 2235 patients (18 to 97 years
of age) with hypertension, non-insulin-dependent diabetes mellitus (NIDDM), re-
cent acute myocardial infarction, congestive heart failure, and depressive disorder
sampled from HMO and FFS systems in 1986 and followed up through 1990. Those
aged 65 years and older covered under Medicare and low-income patients (200%
of poverty) were analyzed separately.
Setting and Participants Offices of physicians practicing family medicine, in-
ternal medicine, endocrinology, cardiology, and psychiatry, in HMO and FFS sys-
tems of care. Types of practices included both prepaid group (72% of patients) and
i
ndependent practice association (28%) types of HMOs, large multispecialty
groups, and solo or small, single-specialty practices in Boston, Mass, Chicago, III,

in HMOs! Policies at the state and fed-
eral levels seek to affect a similar shift
for those who are publicly insured, in-
cluding both Medicare and Medicaid.
Congress has signed legislation that will
give Medicare patients strong financial
incentives to enroll in managed care
plans. Yet, as documented in a recent
literature
analysis,'
little is known about
health outcomes in HMOs for the elder-
ly and the poor, who have historically
tended to favor fee-for-service (FFS)
over HMO systems.
The Medical Outcomes Study (MOS)
was fielded to compare
4-year
health
outcomes for chronically ill patients
treated in well-established HMOs and
FFS plans serving the same "medical
marketplaces" in 3 cities.' To increase
the generalizability of results, adults
with 4 physical conditions (hypertension,
non-insulin-dependent diabetes mellitus
[
NIDDM], recent acute myocardial in-
farction, and congestive heart failure)
and 1 mental condition (depressive dis-

We report here the results of com-
paring changes in physical and mental
health status between FFS and HMO
systems, measured over a 4-year pe-
riod. In contrast to previous MOS re-
ports of outcomes for the average pa-
tient, we focus on outcomes for policy-
relevant subgroups-including patients
aged 65 years and older covered by
Medicare and those near and below the
poverty line. Further, results are re-
ported for patients across all of the
conditions sampled in the MOS and not
just for patients with hypertension and
NIDDM
4
and mental disorders
s,6
METHODS
The MOS was an observational study
of variations in practice styles and of
outcomes for chronically ill adults treated
in staff-model and independent practice
HMOs vs FFS care in large multispe-
cialty
groups, small, single-specialty
groups, and solo practices serving the
same areas. Details of the MOS design,
including site selection, sampling, clini-
cian and patient recruitment, and data

were female, and 29% were interna-
tional medical graduates.
1040

JAMA, October 2,
1996-Vol
276, No. 13
Patient Sampling and Characteristics
Patients followed up longitudinally
were selected from 28 257 adults who
visited an MOS site in 1986; 71.6% agreed
to participate. In 18 794 (92.9%) of the
visits, a standardized screening form was
completed both by the MOS clinician
and the patient. Using criteria docu-
mented elsewhere,' clinicians identified
patients
with hypertension, NIDDM,
myocardial infarction within the past 6
months, and congestive heart failure.
Patients with depressive disorder were
identified independently in a 2-stage
screen, which included
a
patient-com-
pleted form and a computer-assisted di-
agnostic interview by telephone; 80%
of those contacted completed this screen-
ing process.
Patients were selected for follow-up

older; all but 1 reported being covered
by Medicare. (An additional 144 patients
aged into this group during the 4-year
follow-up.) A slight majority (54%) were
female. About 22% were at or below
200% of the poverty line; 16% of those
reported being covered by Medicaid.
Three of 10 eligible for Medicare were
also in the poverty group. Three of 4 had
completed at least a 12th grade educa-
tion; about 1 in 5 was nonwhite.
Patients sampled had the following di-
agnoses: hypertension (n=1318), NIDDM
(n=441), congestive heart failure (n=215),
recent acute myocardial infarction
(n=104), and depressive disorder (n=444).
(These numbers add to more than 2235
because some patients had more than
one
condition.)
1,9
As in previous MOS
analyses,' FFS patients followed up in
this study were significantly older (41.9
vs 32.9 years on average) than HMO pa-
tients,
were more likely to be female
(62.8% vs 57.8%), and were more likely
to be in the poverty group (25.4% vs
18.1%). The FFS patients followed were

als and failure to contact (n=661; 29.6%);
137 (6.1%) who died during follow-up
were included in the analysis. Analysis
of initial health status for those lost to
follow-up for reasons other than death
revealed no differences and loss to follow-
up was equally likely in HMO and FFS
systems. However, younger and pov-
erty-stricken patients were more likely
to be lost from both HMO and FFS
systems. All analyses of outcomes ad-
justed for age, poverty status, and other
variables to take into account this po-
tential source of bias (see "Statistical
Analysis").
Health Status Measures
Summary physical and mental health
scales constructed from the Medical
Outcomes Study 36-Item Short-Form
Health Survey (SF-36) were analyzed
(Table 1). These summary measures
capture 82% of the reliable variance in
the 8 SF-36 health scores estimated us-
ing the internal-consistency reliability
method
The construction of sum-
mary measures, score reliability and va-
lidity, and normative and other inter-
pretation guidelines are documented
elsewhere."

terms of a wide range of clinical and
social
criteria."
Estimates of health outcomes for sur-
vivors only were substantially biased be-
cause deaths were more common among
those with congestive heart failure, aged
65 years and older, and under FFS care;
deaths were less likely for the clinically
depressed group. Differences in survival
rates between FFS and HMO systems
were insignificant after adjustment for
baseline patient characteristics. Thus, al-
ternative methods of coding
deaths"
in
estimating outcomes did not affect com-
parisons between FFS and HMO sys-
tems (MOS unpublished data).
Statistical Analysis
The goal of the analysis was to com-
pare HMO and FFS systems of care in
terms of average changes in health sta-
tus and in terms of the percentages of
patients who were better, the same, or
worse at follow-up. These outcomes were
estimated for all patients, and separately
for subgroups differing
in
age, poverty

I
nternal-consistency reliability=0.91; test-retest
reliability=0.89, which exceed the minimum standard suggested for group-level comparisons."
Mental health
SF-36 Mental Health Summary Scale, standardized to have mean=50, SD=10 in the general US
population.
1
3
I
nternal-consistency reliability=0.87; test-retest reliability=0.80, which exceed the minimum
standard suggested for group-level
comparisons."
Mean changes
Physical health
Calculated for all patients as [(score at 4-year follow-up) -(baseline score)], prorated to adjust for unequal
ti
me intervals. Patients who died during the study were assigned a score of 0 at 4-year
follow-up.
16
A score
of 0 falls about 1 SD below the worst possible score, a score that was observed among MOS survivors.
A score of 0 is also about 1 SD below the worst health state quantified in preliminary studies of an
SF-36-based utility index, which combines health status and mortality. Sensitivity analyses with deaths
scored 1 SD above and 1 SD below a score of 0 did not change conclusions about differences in health
outcomes between fee-for-service and prepaid health maintenance (HMO) plans (MOS unpublished data).
Mental health
Calculated for surviving patients as [(score at 4-year follow-up) -(baseline score)], prorated to adjust for
unequal time intervals.
Categories of change
Physical health

n comparison with
nonresponders
25
are reported here. Results for the 8 SF-
36 scales are documented elsewhere (MOS
unpublished data).
Multinominal (polytomous) logistic re-
gression" methods were used to com-
pare categorical changes (better, same,
worse) in physical and mental health
across HMO and FFS systems for the
total sample and for the subgroups. Ad-
justed percentages for change catego-
ries were generated with statistical ad-
justments
for
the
same baseline
characteristics used in linear models
(Table 2). The X
2
tests of significance
were computed to determine whether
the percentages across change catego-
ries differed between HMO and FFS
systems of care.
Comparisons of outcomes across sys-
tems reported here combine results for
IPA "network" and staff-model HMOs.
As in previous MOS analyses ,

cally or mentally) higher, lower, or as
would be expected at baseline, given their
age and medical condition (Table 2).
In keeping with the logic of an intention-
to-treat analysis, patients were analyzed
according to the system from which they
were sampled. In support of this decision,
the great majority of patients had been in
their system 4 years or more at the time
of sampling and most who switched did
not do so for another 2 years. Thus, more
than two thirds of those who switched
systems during the 4-year follow-up had
been in the type of system they were
sampled from for 6 or more years before
switching. However, because MOS pa-
Chronically III Elderly and Poor Patients-Ware et al

104
1
Table 2 Covariates Used in the Estimation of Regression Adjusted Health Change Scores
Main effects
System of care
Sampled from prepaid health maintenance organization (HMO) or fee-for-service care*
Age
Age
-65
y or age <65 y, classified at baseline
Sex
Male or female

HMO and physical or mental health tertiles
Age ?65 y and poverty
Age
-65
y and physical or mental health tertiles
Poverty and physical or mental health tertiles
Three-way interaction terms
HMO and age
-65
and physical or mental health tertiles
HMO and poverty and physical or mental health tertiles
*Thirty patients (1.9% of those followed) who reported no insurance coverage were included in the fee-for-service
group. All were younger than 65 years. Analyses excluding the uninsured group did not change the conclusions from
comparisons between systems reported here.
tInformation
regarding the comorbid medical conditions was obtained from the patient during a structured medical
history interview conducted by a trained clinician. If information regarding a condition (or conditions) was missing,
an independently derived probability of each diagnosis was substituted. Because of very low prevalence, the
following conditions are incorporated into an index of 11 comorbid conditions: angina (ever), other rheumatic disease,
colitis, diverticulitis, intestinal fistulas, gallbladder disease, liver disease, benign prostatic hypertrophy, varicosities,
cancer, and type I diabetes mellitus.
tients were more likely to switch from an
HMO than from an FFS plan (20% vs
15%; P<.01), estimates of outcomes could
have been biased. This potential source
of bias was evaluated by comparing rates
of switching within elderly and poverty
subgroups along with average outcomes
for those who did and did not switch. As
documented elsewhere (MOS unpublished

fer between the 2 system cohorts for the
total sample (71% vs 70% for FFS and
HMO, respectively), among the elderly
(both 74%), or for those in poverty (62%
vs 60%). Baseline physical health scores
for those followed up and lost to follow-
up did not differ between FFS and HMO
cohorts in analyses of the total sample or
for elderly or poverty subgroups. To de-
termine whether those lost and followed
for health status outcomes had equal sur-
vival probabilities, survival was moni-
tored for all study participants for 7 years
after baseline. Survival probabilities did
not differ for those followed up and those
lost to follow-up. As documented in de-
tail elsewhere (MOS unpublished data),
mental health scores for those lost to
follow-up
were significantly (P<.001)
lower at baseline for both FFS and HMO
cohorts. The same pattern was observed
for elderly and poverty subgroups, with
a significant difference favoring FFS over
HMO for the poverty group (P<.05)
(
MOS unpublished data). However, as
documented in the tables cited in the
"Results," adjusted physical and mental
health scores for the follow-up samples

and FFS systems over the 4-year follow-
up period, we used 2-tailed tests of sig-
nificance throughout.
RESULTS
Adjusted physical and mental health
scores were virtually identical at base-
line for patients sampled from HMO and
FFS systems (Table 3). In relation to pub-
lished norms for the US general popula-
tion," MOS patients scored at the 24th
and 35th percentiles for physical and men-
tal health, respectively, indicating sub-
stantially more physical impairment and
emotional distress than experienced by
the great majority of adults. During the
4-year follow-up, average changes in
physical and mental health were indis-
tinguishable between HMO and FFS sys-
tems. Physical health scores declined
about 3 points in both systems, lowering
the average patient to the 19th percentile
at follow-up.
Mental health improved
slightly in both systems, raising the av-
erage to about the 38th percentile.
The MOS had sufficient statistical
power to detect differences in health
outcomes as small as 1 to 2 points be-
tween HMO and FFS systems of care.
According to published interpretation

Systems for Elderly and Nonelderly Patients
ever, the categorical analyses called at-
tention to substantial variation in out-
comes. Physical health scores at follow-
up differed (from those at baseline) for
45% of patients; about
30%
declined and
15% improved, more than would be ex-
pected due to measurement error. The
reverse pattern-improvement more of-
ten than decline-was observed for men-
tal health scores (Table 3).
Variations in Outcomes for Elderly
and Poverty Groups
The average adjusted physical decline
was greater for elderly than nonelderly
patients
(0=-5.8
vs -1.9; P<.001);
36%
and
26%
of elderly and nonelderly pa-
tients, respectively, scored worse at fol-
low-up than at baseline (P<.001) (Table
3). Elderly patients scored higher in men-
JAMA, October
2, 1996 Vol 276, No. 13
*Scores are adjusted for demographics, chronic disease, and design factors. The 4-year change scores for physical health (but not mental health) include deaths scored

the poverty group.
Differences in Outcomes by System:
Elderly and Nonelderly
Although adjusted baseline scores
were equivalent for elderly and nonel-
derly patients in comparisons between
HMO and FFS systems (Table 4),
changes in physical and mental health
scores over time for the elderly in HMO
and FFS plans were significantly dif-
ferent from those for the nonelderly
(F=2.1, P<.05, and X2=35.6, P<.001 for
physical
health;
F=1.3,
P>.05, and
Xz=25.9,
P<.01 for mental health) (Table
4).
Physical health outcomes were, on
average, more favorable for nonelderly
patients in HMOs, while physical health
outcomes were more favorable for el-
derly patients in FFS.
Although we could say with statistical
confidence that the patterns of average
change scores were different across HMO
and FFS systems for elderly and nonel-
derly patients, only pairwise comparisons
between categories of changes were sig-

2235
45.0
-3.0
-3.8 to -2.2
29 56
15
48.5
1.1
0.3 to 1.9
15
63 22
Service system
Prepaid (HMO)
1073
44.9
-3.1
-4.3 to -1.9
30
X
2
=1 .5
55
15
47.9
1.2
0.0 to 2.4
14
X
2
=1 .3_

15
X
2
4.3
65
20
Nonelderly
1413
45.7
-1.9
-2.9 to -0.9
26 58 17
47.7
1.3
0.3 to 2.3
15
63,.
22
Poverty status
Poverty
489
44.4
-3.6
-5.2 to -2.0
33
X
2
=4.6
51
17

4-y A$
95% CI§
Worse
Same
Better Baseline (SE)
4-y
At
95% CI§
Worse
Same
Better
Elderly
822
X
2
=19.211
X
2
=7.1$
Prepaid (HMO)
346
43.4 (0.7)
-7.0
-8.8 to -5.2
54
37
9
50.1 (0.8)
1.3
-0.5 to 3.1

1.5
0.1 to 2.9
12
68 20
Fee-for-service.
686
45.6 (0.5)
-2.4
-3.8 to -1.0
29
57
15
48.5 (0.5)
1.1
-0.7 to 2.9
16
64
19
Test for equivalence
of differences in
outcomes between
prepaid and fee-for-
service systems
among elderly vs
nonelderly subgroups
1`6,5,8=2.1#
X
2
=35.6
**

of change are equal.
*Significance tests for average
scores
indicate whether the mean score for the HMO group
differs
from the mean score for the
fee-for-service group.
§lt
the 95%
confidence
i
nterval (CI) does not
i
nclude
0, then average change scores are larger than expected by chance (P<05).
II
P=.01.
1P=.02.
#P<.001.
**P=.03.
Table 6 Physical and Mental Health Outcomes in Prepaid and
Fee-for-Service
Systems for Initially III Patients in the
Poverty
Group
Average Scorest

Categorical Change,
%#



Same

Better
X
3
=10.911

X
2
-4.1
Prepaid (HMO)

90

35.21(0.8)

-2.0#

-5.1 to 1.1

33

45

22**

37.1 (0.9)

4.5

16

34

49
*Scores are adjusted for demographics, chronic disease, and design factors. The
4-year change scores for physical health (but not mental health) include deaths scored
at 0 at 4-year follow-up.
tSignificance
tests for average scores indicate whether the mean score for the health maintenance organization (HMO) group differs from the mean score for the fee-for-service
group.
$The
Xz
statistics for categorical
change refer to the results shown below and indicate whether the patterns of change are equal across the following pair of
rows.
§If the
95
1
/6
confidence
i
nterval (CI) does not include 0, then average change scores are
larger
than expected by chance (P<.05).
II
P=.006.
1P 014.
#P<.001.
**P=.04.

study site. A formal test for a statistical
interaction between plan and site re-
vealed that mental health outcomes in
1044

JAMA, October 2,
1996-Vol
276, No. 13
Physical
Health'
AAeMaI
1t
Nlth*
HMOs differed significantly across the
three sites (F=2.44, P<01).
Differences
in Outcomes of Poverty
and Nonpoverty Groups by System
As shown in Table 5, comparisons of
physical and mental health outcomes
across HMO and FFS systems produced
different patterns of results for poverty
and nonpoverty groups (F=2.7, P<.01,
and X
2
= 24.2, P<.02 for physical health;
F=4.2, P<.001, and X
2
=23.0, P<.03 for
mental health). Only the pairwise com-

COMMENT
Limitations
Limitations of the MOS have been
discussed
extensively,""
but some limi-
tations and potential sources of bias war-
rant special emphasis here. Analyses of
4-year health outcomes have been a long
time coming because of the many meth-
odological challenges faced by the MOS.
Do results apply to current health care?
If cost-containment pressures have
in-
Chronically.Ul_EldeJly.and
Poor
Patents-Ware
et-al
Physical Health*

Mental Health*
s
Average Scores
Categorical
Change,
%t
Average Scores
Categorical Change, %t
No.
Baseline (SE)

Fee-for-service
194
45.1 (0.8)
-3.3
-5.7 to -0.9
36 46
18
47.9 (0.8)
1.3
-1.2 to 3.8
17 57 26
Nonpoverty
1746
X2
=2.34
Xz=2.59
Prepaid (HMO)
879
45.3 (0.5)
-2.2
-3.6 to -0.8
24 62
13
47.9 (0.5)
1.4 0.2 to 2.6
11
70 18
Fee-for-service
867
45.1 (0.4)

groups may be at an even greater risk
today. If information systems for moni-
toring and improving the quality of care
are better now and if health promotion
and disease prevention initiatives are
more successful in HMOs, MOS results
may not apply to current health care.
The MOS was not a randomized trial;
such trials are rare in health care policy
research.'a'
9
Although quasi-experimen-
tal
methods
2
°
achieved equivalent aver-
age baseline health status scores for
nearly all
pairwise
-
comparisons
between
FFS and HMO systems of care, unmea-
sured risk factors could have biased es-
timates of differences in outcomes. Fur-
ther,
differences in outcomes that
occurred "on the watch" of the FFS and
HMO systems are not necessarily their

tems because adjusted physical health
scores at baseline did not differ between
FFS and HMO cohorts followed within
the total sample or for elderly or pov-
erty subgroups (Tables 3 through 5).
Further, all study participants were fol-
lowed up through 1993 to determine their
survival." Seven years after baseline,
those included and not included in this
4-year analysis were equally likely to
have survived (MOS unpublished data).
Two of 10 HMO patients switched to
an FFS plan by the end of the 4-year
follow-up. Comparisons between sys-
tems could have been biased had these
rates differed within elderly or poverty
subgroups or had switchrs experienced
different outcomes than nonswitchers.
However, rates of switching did not dif-
fer for elderly or poverty subgroups,
JAMA, October 2,
1996-Vol
276, No. 13
and system differences in physical and
mental health outcomes were indistin-
guishable for those who stayed in the
same system, in comparison with those
who switched (MOS unpublished data).
Thus, it is unlikely that conclusions about
system differences in outcomes were bi-

intervals were too large for meaningful
interpretation of some comparisons that
yielded insignificant differences in out-
comes. Examples include comparisons
between IPAs, the fastest growing form
of HMO, and staff-model HMOs; Med-
icaid and
non-Medicaid
groups could not
be compared with precision, and com-
parisons between plans within sites were
relatively imprecise, although the dif-
ference in 1 site was large enough to
reach significance. (This difference would
not have been significant with an ad-
justment for multiple
comparisons.)
For
many comparisons, the MOS cannot rule
out large differences in outcomes in ei-
ther direction.
Interpretation of Results
The success of HMOs in reducing
health care utilization has been docu-
mented in numerous
studies?
,
'
9
With few

an HMO were more likely
(than those sampled
from
an FFS plan)
to have a poor physical health outcome
in all 3 sites studied. Second, patients in
the poverty group and particularly those
most physically limited appear to be at
a greater risk of a decline in health in an
HMO than similar patients in an FFS
plan. Finally, MOS results suggest the
need for caution in generalizing conclu-
sions about outcomes across study sites.
Mental health outcomes for Medicare
patients differed significantly across
HMOs, suggesting that their perfor-
mance relative to FFS plans may de-
pend on site.
Previous
studies
;
'
-21
that found no dif-
ferences in health outcomes between
FFS and HMO plans followed patients
for only 1 year. Were these studies too
brief to draw conclusions about health
outcomes?
Supporting

what specific treatments have been
linked to physical and mental health out-
comes as measured by the SF-36 Health
Survey? Adverse medical events were
too rare for meaningful comparison be-
tween plans in the MOS and were moni-
tored
only
during
the first 2 years of
follow-up' However, these events were
significantly related to health outcomes,
as hypothesized. Declines in SF-36 physi-
cal health scores were significantly more
likely among patients who experienced
a new myocardial infarction, weight loss
sufficient to warrant a physician visit,
Chronically III Elderly and Poor Patients-Ware et al-

1045
and chest pain sufficient to require hos-
pitalization (MOS unpublished data).
These preliminary MOS results are con-
sistent with published studies that have
linked SF-36 health scores to disease
severity and to treatment response, in-
cluding severity of soft-tissue
injuries"
and changes in hematocrit among chronic
dialysis patients 2

studies using the SF-36 are cited else-
where
.15
Identification of the clinical
correlates of changes in physical and
mental health status warrants high pri-
ority in outcomes and effectiveness re-
search."
Future
studies
should
address
whether variations in the quality of care
explain differences in outcomes across
systems. The MOS patients in HMOs
reported fewer financial barriers and
better coordination of services in com-
parisons
with equivalent FFS pa-
tients.
12,3
s
Analyses of primary care qual-
ity criteria indicated that those in FFS
systems experienced shorter treatment
queues and better comprehensiveness
and continuity of care and rated the qual-
ity of their care more favorably.
12,3'
D

tor outcomes while retaining the option
of analyzing the 8-scale SF-36 health
profile
on
which they are based. The
reporting of results in change catego-
1046

JAMA, October 2,
1996-Vol
276, No. 13
ries in terms of better, same, and worse
may simplify the reporting of outcomes
to diverse audiences and may make re-
sults easier for them to understand. More
practical data collection and processing
systems-under development-and ad-
vances in understanding of the specific
treatments that improve health scores
the most and the clinical and social rel-
evance of those improvements will in-
crease their usefulness in improving pa-
tient outcomes."
Policy Implications
The MOS results reported here and
previously' for the average chronically
ill patient constitute good news for those
who consider HMOs as a solution to ris-
ing health care costs. Outcomes were
equivalent for the average patient be-

pared, there were no significant differ-
ences between FFS and HMO plans and
there were no noteworthy trends (MOS
unpublished data). Poverty status, as
opposed to Medicaid beneficiary status,
was the better marker of risk of a poor
health outcome in an HMO. This is not
a new finding. The Health Insurance
Experiment also observed that some
health outcomes were less favorable over
a 5-year follow-up for low-income pa-
tients in poor health in 1 HMO com-
pared with equivalent patients under
FFS care."
Final Comment
In this article, the MOS has docu-
mented variations in health outcomes
for chronically ill patients that cannot
be explained in terms of measurement
error. For elderly Medicare patients and
for poor patients, variations in outcomes
during a 4-year period extending
through 1990 were linked to FFS and
HMO systems of care (the latter were
predominantly
staff-model
HMOs).
Other explanatory factors included prac-
tice site, suggesting that health out-
comes should be monitored on an ongo-

$7.75 for photocopies or $5 for microfiche. Outside
the United States and Canada, add postage of $4.50.
The postage charge for any microfiche order is $1.50.
Collection of 4-year health outcome data and
preparation of this article were supported by grant
91-013 from the Functional Outcomes Program of
the Henry J. Kaiser Family Foundation, at The
Health Institute, New England Medical Center,
Boston, Mass (John E. Ware, Jr, PhD, principal in-
vestigator).
Design and implementation of the
MOS were sponsored by the Robert Wood Johnson
Foundation, Princeton, NJ; the Henry J. Kaiser
Family Foundation, Menlo Park, Calif; and the Pew
Charitable Trusts, Philadelphia, Pa. Previously re-
ported analyses were sponsored by the National
Institute on Aging, Bethesda, Md; the Agency for
Health Care Policy and Research; and the National
Institute of Mental Health, Rockville, Md. Partici-
pating plans, professional organizations who as-
sisted in recruitment, and our many colleagues who
contributed to the success of the MOS are acknowl-
edged
elsewhere.`
The authors acknowledge the
thorough and constructive suggestions received
from Allyson Ross Davies, PhD, Kathleen Lohr,
PhD, Edward Perrin, PhD,
Dana
Safran, SeD, and

Greenfield S, Rogers W, Mangotich M, Carney
MF, Tarlov AR. Outcomes of patients with hyper-
tension and non-insulin-dependent diabetes melli-
tus treated by different systems and specialties:
results from the Medical Outcomes Study. JAMA.
1995;274:1436-1474.
5.
Wells KB, Hays RD, Burnam MA, Rogers W,
Greenfield S, Ware JE. Detection of depressive
disorder for patients receiving prepaid or fee-for-
service care: results from the Medical Outcomes
Study. JAMA. 1989;262:3298-3302.
6.
Rogers WH, Wells KB, Meredith LS, Sturm R,
Burnam A. Outcomes for adult outpatients with
depression under prepaid or fee-for-service financ-
ing. Arch Gen Psychiatry. 1993;50:517-525.
7.
Stewart AL, Ware JE, eds.
Measuring Func-
tioning and Well-being: The Medical
Outcomes
Study Approach. Durham, NC: Duke University
Press; 1992.
8.
Kravitz RL, Greenfield S, Rogers WH, et al. Dif-
ferences in the mix of patients among medical spe-
cialties and systems of care: results from the Medical
Outcomes Study. JAMA. 1992;267:1617-1623.
9.

A User's
Manual. Boston, Mass: The Health Institute, New
England Medical Center; 1994.
14.
Ware JE, Kosinski M, Bayliss MS, McHorney
CA, Rogers WH, Raczek A. Comparison of meth-
ods for scoring and statistical analysis of
SF-36
Health Profiles and Summary Measures: summary
JAMA, October 2,
1996-Vol
276, No. 13
of results from the Medical Outcomes Study. Med
Care.
1995;33(suppl
4):AS264-AS279.
15.
McHorney CA, Ware
JE,RaczekAE.TheMOS
36-Item Short-Form Health Survey (SF-36), 11:
psychometric and clinical tests of validity in mea-
suring physical and mental health constructs. Med
Care. 1993;31:247-263.
16.
Diehr P, Patrick D, Hedrick S, et al. Including
deaths when measuring health status over time.
Med
Care. 1994;32(suppl
4):AS164-AS172.
17.

Lurie N, Moscovice IS, Finch M, Christianson
JB, Popkin MK. Does capitation affect the health of
the chronically mentally ill? results from a random-
ized trial. JAMA. 1992;267:3300-3304.
22.
Retchin SM, Clement DG, Rossiter LF, Brown
B, Brown R, Nelson L. How the elderly fare in
HMOs: outcomes from the Medicare competition
demonstrations.
Health
Sere
Res.
1992;27:651-669.
23. Clement DG, Retchin SM, Brown RS, Stegall
MH. Access and outcomes of elderly patients en-
rolled in managed care.
JAMA.1994;271:1487-1492.
24. Beaton DE, Bombardier C, HoggJohnson S.
Choose your tool: a comparison of the psychometric
properties of five generic health status instruments
in workers with soft tissue injuries.
Qiual
Life Res.
1994;3:50-56.
25.
Beusterien KM, Nissenson AR, Port FK, Kelly
M, Steinwald B, Ware JE. The effects of recombi-
nant human erythropoietin on functional health and
well-being in chronic dialysis patients.
J

1995;22:1193-1196.
29. Phillips RC, Lansky DJ. Outcomes manage-
ment in heart valve replacement surgery: early
experience.
J Heart Valve Dis.
1992;1:42-50.
30.
Okamoto LJ, Noonan M, Kirchdoerfer LJ, Bayer
JG, Kellerman DJ, Saiers JA. Quality of life in
patients with severe asthma: baseline health pro-
file and effects of fluticasone propionate aerosol.
Ann Allergy Asthma Immunol. 1996;76:1-7.
31.
Rampal P, Martin C, Marquis P, Ware JE, Bon-
fils
S.
A quality of life study in five hundred and
eighty-one duodenal ulcer patients. Scand
J
Gas-
troenterol.
1994;29(suppl):44-51.
32. Stucki G, Liang MH, Phillips C, Katz JN. The
Short Form-36 is preferable to the SIP as a generic
health status measure in patients undergoing elec-
tive total hip arthroplasty. Arthritis Care
Res.
1995;
8:174-181.
33.

1988;319:1197-1202.
37.
Rubin H, Gandek B, Rogers WH, Kosinski
Y,
McHorney C, Ware JE. Patient's ratings of outpa-
tient visits in different practice settings: results
from the Medical Outcomes Study. JAMA. 1993;
207:835-840.
38.
Davies AR, Halpern R. Health Care Outcomes:
An
Introduction. Irving, Tex: Voluntary Hospitals
of America
Inc;
1993.
Chronically III Elderly and Poor Patients-Ware et al

1047